The purpose of this project is to continue to assess the neuropsychiatric status of individuals who have abused cocaine and other drugs over a long period of their lives. However, there are few studies which used a detailed neuropsychiatric examination to classify different neurological syndromes that might be associated with the use of drugs of abuse. We have thus started to carry out thorough neurological and neuropsychological examination in subjects who are chronic cocaine or polydrug abusers and who are seronegative or seropositive for HIV. The results of these examinations continue to show evidence of nystagmus, abnormal eye pursuit, abnormal saccades, decreased reflexes, and increased jaw jerk. The presence of nystagmus and increased jaw jerk in these subjects may be related to cocaine effects on brainstem pathways. The reflex and sensory abnormalities appear to correspond to a bilateral symmetric neuropathy. Neuropsychological testing show attentional deficits in these patients. These results provide evidence for possible neurological abnormalities pursuant to drug abuse.